Potential indicating and measuring device.



E. 0. SGHWEITZER. POTENTIAL INDIQATING AND MEASURING DEVICE.

, APPLICATION FILED 110mm, 190s.

- Patented NOV. 5,1912.

deit of v 111 ented p oi in nt in- P provl' de the terminal: i. Jlg'gilightledyit isnotcliargeglf tempera ureicoetlici'cuha' hig (emactuatesutg ihut ?it 0 mediateac at 1 s for; ekample mediate ljpgh willause th' --v ,s onds wr ith-nut I applied to the erminal. the device tooperate successa We!" the dev l have found tes to potential indiyices,and HS pr ncimple, practical, ."fportable indicating is which can the-u' ed' t ing'and 1'heas-:

shown for carrying an: indicating" l *ii'icandescenfi lamps, evige suehas f a- W 1 1e like, (5o||l('l;l')e'*'1 d resistance, 1 emativeteliiperat ua'ent "will pass tl'nxlugh ien through the"-indicats way thedevice can be nil-whose potential, or ;is.,desired to ascertain,anneeted to ground or :the rcuit, and when thusar al' is charged, theine actuated ,.e as for exused the lamps will be indicate ofcou aargedffate th ance having ..a negative 11 potential, will elv pp'euate iotaaotu ate the in lie-at u "ha'lh'wzi rotentiailk aviHaunt t l dmso'iin'lamps.

n 6: Letterslatent. ApplicationtiledNovember 12,1908. Serial No.462,216. I

Cook and State a certain new-and otential Indicating ces, of which thefollowconcise, and exact de- 4 being had to the accomfornling' a p ai't'of this- 'ely low; po

)refeiahly ure coethrse that If the lamps are the terminal broken away;Fig. 3 is a diagramo fied arrangement of lamps. a, 1 v

' Referring Zfirsti; to,F giwil lztshow" along a cap having a; metal t-i5 their resistance hecome less as thev become somewhat heated by thepassage of the cur-- i Patented N ti, 1912.

fully j upon a ran e of potentials running from several hun reds up toseveral thousandvolts. v a I As a preferredarrangement when lamps 0 areused, I alsoempl'oy a switch by -u'hich one or more of the lamps can bethrow n into circuit. For example, I may use tln'ee lamps and arrangethe switch so that either oneor two,- oixallthree, may he included-lathecircull! as 'deslred.

In the operationof this device it lias'been found convenient to usethreeresistancesi \VlllCll have approxlmately 18000 olimsnreslst ance, andthree lamps, preferablv each -7 having about; EZO-phmS res1stance.-Consid: eriugthe \"olt: 1ge of the circuit and the 18000 ohms resistanceit canbe readilyseen that if approximately; onehalf; ampere flows,whichjs sl fiiqient to light one lamp to 7' hrilliancy the volt-age ofthe circuit is .9000 volts. N ow-if for instance t-wo lamps are lightedto hrilliancy, the-voltage of the circuit 7 would be 18000 yolts. Themanipulators of e the device can, by knowing the approximate 30.'.currentwhich ittakes to lightone or more lamps to varying degrees ofbrilliancy, estimate within t-wentyper cent. by the indications of thedevice, whatis the voltage of the circuit under test, and thisissufficient for s5 he purposes for which this device is intended. Thus byoperating the switch so as to cause one orinore of the lamps tobelighted 'to' full candlepower for eiiample,- and knowing the resistanceof the device, the potential can be substantially calculated; 1

In the'accompanying drawings Figure 1 is longitudinal section of apotentialindi" eating device embodying my present invention; Fig. 2 is aplan view ofa modified form of .device with its cover iipartiallyw amodi-r made of i i-nsulating i which serves as ye Atio.

. v "tup r eferal-il e 'e npenatl re coetlic lent' t rig"the'meharacterlsticsa mfi ehai m atemalflpref s 10041 user can'easilydetermine whether itis 6000 volts or,11000, and this sockets tial notbeing sutiiciently high to light the the resistances of the rent throughthenn Such resistances as is 1 well known in the art, have a highnegative temperature coeiiicientand consequently the amount of currentflowing through them increases rapidly if they are allowed to re main incircuit even though the voltage to which they are subjected isconstant.These resistances are electrically connected by metal connectors 4-4. Afuse in the form of a glass tube 5, containing a fuse 0, ispreferablyemployed and located at the forward end of the tube or-sheathand extending through such end of the same, and through the metal cap 2to the forward end of thelatter, where it meets and is in contact wit-hthe metal tip 7. The fuse device is understood to be in electricalconnection also witl-ij-the adjacent resistance 3. 3 At the rear end ofthe tube or sheath 1 are shown a set or series of lamps 8-1-8, fittedinto 9 9-9, which are connected in parallelz with one another and inseries with the resistances 3. Near the end of the sheath 1 is shown adisk' lt), which can serve as a guard for the hand when using thedevice. The circuit conductor 11 is extended through the end ofthe-sheath 1, and is understood to be connected with ground or to someother part of the circuit under test. The device will be used byapplying the tip 7 to the terminal to be tested, and connecting theconductor 11 with ground or some other part of thecircuit If=theterminalunde-r testis charged, the lamps 8--8 will be lighted. If thisoccurs immediately, 7 the potential is high, but if the lamps light upslowly the. potential is comparatively low. In case of the slow lightingof the lamps, it will be seen that such lighting is due tothe loweringof the resistance of the resistances 3-3-by the heating of, the same toa point where enough current can pass through them to light the lamps,the potenlamps immediately through the normal-or cold resistance of theresistance 3. By noting the rapidity with which the lamps lightup aperson who is accustomed to the use of.:,,my device can readilydistinguish between voltages which are considerably dif: ferent fromeach other. For instance, the whether the circuit tested is of 600.volts or two thousand, or

without reference to the switching apparatus described in connectionwith Fig. 2, but merely by noting the rapidity with which the lampslight up and their final brilliancy, v y

In Fig, 2-1 have shown a-modified form, of the device. consistingessentially ofv a' box-like member 12, containing three resistances,3-3-4),

to the box-like structure conductor 17, which leads to ground.

I for the lamps,

ductors 11 of Fig. 1, lamps v they are As a result the actionof--a,,-current on them preferably the same as device of Fig. 1. Theseresistances are connected n serieswith one another by conductors H t-1t.The box-like structure 12 is used win-re as long a device as that shownin Fig. 1 would be objectionable, the length being much reduced byfthearrangement of Fig. 2. glass fuse 5 is preferably employed in this casealso, being inclosed in a tubular shat't 5 15 made of insulatingmaterial and secured with a wooden cap 2, having a metal tip '4'.

A short'insulating tube 10 attached to;

of the 1.0 12, and: v

the opposite side end 12 and provided contains the conductor'li leadingto ground 1 w u 3 lube 16 also serves as a handle. 7 incandescent lamps8-8-S are shown,

A series mounted upon a box or case 18, having switching mechanism bywhich the lamps can be thrown into and out of circuit as desired. Theform of switching mechanism shown comprises a sliding rod 19, having aportion of its length 19 material, and provided with a handle 20,

and the inner port-ion of its length 19 made This rod slides in a metalguide '21. The guide 21 is connected \Viththe' i e-- of metal.

made ofinsulatmg sistance 3 by a conductor 23. Contacts 25, a

26, 27 are provided, and arranged to receive the rod 19 and connect withthe sockets for the lamps 8-8--8. Individual connec' tions are shownbetween contacts 25, 26, and 27 and the lamps 8. The other side of thelamps is connected in parallel to a con ductor 24 y sliding-the rod 19back and forthiby means of its handle 20,- -eit-her one-or two, or allthree, of the lamps which connects in turn with the 8-8-8 can'beconnected v in circuit. This device will housed as described inconnection with the device of 1, but it has the further feature of theswitch is better, there being no fluctuation or chargsatisfactory andaccurate.

In Fig. 3 I have shown rangemen-t of lamps are connected in parallelwith one another. and also in parallel with one of the resistances 3.

It. will be understood thatchanges and' modifications can bemade withoutdepartfrom the spirit of theinvention.

so that by manipulating the..-- handle 20 tocause oneor more'of'thelamps to be lighted to normal brilliancy thepoby having the lamps .115and 17 of Fig.2 these ingeft'ect, so that. their indication is more v amodified arlamp connect1on,.1n which the the indicating and measur nginstrument; "comprising in? combination an" indicating ber of differentindications variations of current flow, and a resistance .deffceyincluding arbon in itslcom position, saidindicati'n as e andresistance device being ielude in electric circuit," where by pdtenti'al*niayj-be indicated and measured indicating devl variations of currentflow, a resistance device 1 lr ripgg as; negative temperaturecoetlicient; means for including said devices in an electric circuit,and means for varying .the current in said eirciiit 3. A potentialindicating and measuring instrument, comprising in combination aresistance element in the form of a pencil of carbon compound having anegative temperature coeflicient, anincan'descent electric lamp, andmeans for connecting said lamp and carbon compound pencil in an electriccircuit. I

4. In a potential indidator in combination, a resistance, a plurality ofindicating devices, means for including one or more of devices'incircuit as desired, and means for including the potential indicator in acircuit to be tested.

A potential indicator comprising in combination, an indicating devicecapable of giving a number of different indications in response tovariations of current flow, and a. plurality of'resistances connected inseries with said device and with each-other,

said resistances havinga combined negative temperature coeflicient.

6. A. device of the .class specified, comprising resistance rods,incandescent lamps, an insulating member forming a portable holder forsaid lamps and rods, means by' which thevdevice can be included in acircuit to be tested, and a switch for including one or more of thelamps in circuit as desired.

7. A. device of the class specified, comprising resistance rods, aninsulating member forming a portable holder for said rods, a fuse, ametal cap for making connection with a terminal to be tested, andincandescent lamps mounted in sockets on said insulating member, saidresistance rods,- fuse, metal cap, and lamps being serially connectedfor purposes of testing.

8. A device of the class specified, comp I device by permitting current*tojen'du-re thr 'u indications in response to" prisingresistance rods,an insulating mem-- I fonelby "one into andjpu'tiza circuit saidre;m'responsjejto with a terminal tof-be tested incai-idescent lampsmounted in sockets on said ulating member, and a switch forrclitingsaid' laiii: )3

sistancef rods, fuse, 'metaljcap, andblainlis beingf serially'connectedi "forf f pm-pa es" of testing; I {i 9 A'high potentialindicator comprising in combination, a device capable ofmakinga seriesof different indications in response to variations in current flow, andresist? ance element having a high resistancedri v series with saiddevice and-also having a high temperature eoeflicient whereby the amountof'current flowingt-hrough said die-L8 vice varies rapidly giving "aseries ofvarying indications for a given potential."

10. A device of theclass specified; com prising an insulatingniembei-formingai portable holder, carbon-"compound rods hav- 3 mg anegative temperature 'coefiic-ient car-- ried by said holder, a fuseificircuit with said carbon compound; rods, a 'itietal' cap having a metaltip in circuit with said fuse for making connection with a circuit to betested, and a set of lamps connected in cir cuit with the carboncompound rods at the end of the same opposite said metal ti 11. A deviceof the character described, comprising-a high resistance encil' in com-5 bination with a plurality 0 incandescent lamps andnneans forconnecting one or more of said lamps in parallel relation, the lampcircuit being serially included with said resistance .pencil.

12. In a potential indicator in combination, a portable case, resistanceelements carried in said case, a tube inclosing a fuse projecting fromsaid case, and a metal contact supported by said tube, said contact,fuse'and resistance elements being electrically connected.

13. In-a potential indicator in combination, a case supporting anindicating device;

of pencil resistance elements eara plurality ried side, y side in saidcase, a tube projecting from said case inclosing a fuse, a cap carriedby said tube supportinga metal contact, and means for connecting saidcontact fuse, in circuit.

14. A potential indicator comprisin in combination an indicating devicecapable of giving a number of different indications in response tovariations of current flow, and a high resistance element formed of acarbon eompol'ind and connected in series with said device. i

15. A potential indicator comprising in combination, an indicatingdevice consisting of a plurality of incandescent electric lamps, a highresistance clement formed of a carbon compound connected in series withsaid device, and a switch for introducing one 01' more of'said lamps incircuit.

resistance elements, and indicator 115 16. A high potential measuringinstrument comprising in combination, an indicating device capable ofgiving a series of indicaticnsin response to different current valuesand a high resistance carbon element in series with said indicatingdevice whereby the curreiitflowing through said device may be variedrapidly for any given potential give a series of indications.

fr; A ment comprising in combination, an indicating device having meansfor giving a series-of indications response to variations in currentflow, and a resistance element in serieswitli said indicating devicehaving a high resistance and also having a high temperaturecoefiicientwhereby the.

" amount of current flowing through the instrument varies rapidlygivinga series of nient comprising in combinat1on, an ind catvaryinindications for a given p0ten tia1..

high potential measuring instruing device having means for giving aseries high potential measuring instru of indications in response tovariations in current flow, and a carbon resistance e1e '25 went inseries with said device'whereby the} current flowing through said devicevaries E A rapidly on a given potential to give a series of indications.I

19. A high potential indicator comprising in comb nation, an indicatingdevice capable of giving a number of diiierentindications EDMUND O.SGHWEITZER.

Witnesses: i

A. MILLER Bnnrmnn, C. B. CAMPBEL

